He said some 1,400 passengers, scheduled to fly to Hamburg, Dusseldorf, Copenhagen and domestic destinations, were affected by the cancellations.

The problem was eventually solved around 8 p.m. and operations were functioning normally on Monday. A commission will investigate the source of the attack, Kubicki said.

LOT Airlines said no airborne planes were affected.

A representative at LOT told CBS News on Monday morning that the hackers attacked the airline's internet network, affecting email and web access in their offices. It was not a targeted attack to their flight plan computers.

The biggest effect, the airline official said, was that they could not issue flight plans during the outage.